Guiding rolls for slabs in continuous casting plants are subject to high wear, in particular in the part in contact with the product, and for this reason must be appropriately either maintained or replaced.
Currently the types of rolls mostly used as guides for the casting in continuous slab casting plants are:                solid body rolls with central or peripheral cooling (PDR=Peripheral Drilled Rolls), where solid body roll means a roll in which both the part in contact with the slab and the one on which the bearings and the supports are mounted consist of an appropriately processed single piece;        rolls with jacket keyed on a shaft by means of cotter, these rolls also having a central cooling of the shaft or a peripheral cooling on the jacket.        
Disadvantageously, the solid body rolls imply high costs and long production times. In particular, being made in a single part, they require procuring raw material, cutting to size and processing the roll body. These rolls made in one piece, supported laterally by bearings, envisage being correctly cooled by making through holes in the body of the roll itself, which is currently very costly to make. Furthermore, the roll, once it has been normally worn by the continuous contact with the advancing material, must be appropriately reconditioned and then replaced, thus implying costs for machine downtime and worn material disposal.
On the other hand, the use of rolls with jacket keyed on the shaft has the disadvantage of requiring a suitable device (press) for disassembling the wear element (jacket) from the shaft in the roll. Such an operation often causes damage to the shaft and to the jacket itself.
Furthermore, in the case of rolls with jacket keyed directly onto the shaft, the type with peripheral cooling (PDR) is more efficient because the water is distributed from the channels closer to the contact surface with the hot slab; the difficulty of this configuration, however, concerns the cooling channels made in the jacket which must ensure sealing with respect to the material and interior cleanness to prevent the risk of clogging.
Finally, in case of rolls with jacket with central cooling of the prior art, a single central channel is obtained in the inner shaft. The cooling is less effective in this solution because the peripheral zones of the roll, closest to the slab, are not cooled in optimal manner. It is thus felt the need to make a slab guiding system which can overcome the aforesaid drawbacks.